Alternating-current motor.



V. A. FYNN.

ALTERNATING CURRENT MOTOR.

APPLIOATION FILED JULY 10, 1913.

Patented June 23, 1914;.

55 W F TTORNEV UNITED STATES PATENT VALERIE ALFRED FYN'N, OF ST. LOUIS, MISSOURI, A

TRIC MANUFACTURING COMPANY, (3F $1. ILGUIS, MISSD R.., .E; GORPQRAT OF MISSOURI.

A1TEENATING--CUEELENT MQIOlEZ.

Application filed July 18, 1918. Serial No. TEE-75.

To all whom it may concern:

Be it known that l, VALisnn ALFRED FYNN, a subject of the King of England, residing at the city of St. Louis, State of Missouri, have invented a certain new and useful Alternating-Current Motor, of which the following is such a full, clear, and exact description as'f will enable any one skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, forming part of this-specification.

My invention relates more particularly to constant speed alternate-current commutator motors with phase compensation, and its purpose is to enable the starting conditions to be chosen without regard to the running conditions and to so arrange the connections that it'is possible to change the starting connections into the running connections without interrupting the circuit of the motor and without creating any short circuits.

My invention enables machines of the type referred to, to be designed for the best start: ing conditions and to be operated at the most suitable magnetic densities.

In carrying out my invention, I prefer to make use of a centriiugal switch for chang ing the connections after the motor has reached a certain speed. 7

My invention will be better understood by reference to Figure 1 of the accompanying drawings which illustrates its application to a single-phase induction motor, the rotor of which carries a squirrel cage as well as a commuted winding. Figs. 2, 3, i and 5 show the connections for each position of the controlling switch."

The stator winding is carried out in the manner usual for single-phase motors but is provided with two taps, or it may be said to be divided into three parts, 41, 10 and 11, which are all connected in series and coaxially disposed. The rotor carries a corn muted winding 5 and a squirrel cage winding 22, which is preferably separated from the former by more or less magnetic material. The commuted winding is short-ciao united by means of the working brushes 6, 7, along the axis of the stator winding, It also cooperates with exciting brushes 8, 9, which are displaced by ninety electrical degrecs from the working brushes. The brush 8 is connected to the stator winding between the groups 41 and 10 thereof. Brush 9 is connected to t e stationary contact form mg part of the centrifugal switch. This switch is operated by the rotor by way of the shaft 12 and wheels 13 and A. The weights 1.5 of this switch control the sliding contacts 16, 1?, coiperating" with the statlonary contacts 20, 2.1, 23 and 18, 19 respectively. One cfthe mains 32 connected. to one end of the stator winding il. while the other main 33 is connected to the staionary contacts 520 and 18 of the centrifugal, switch. A tap brought out between the parts 10 and 11 of he stator wit is connected to contact 21, and :3. end of part 11 nected to the st of this improved [it starting, the IHOV- the ccnt ii ing contacts 13 and i switch are in the pos n shown in the fig me, which will be re red to as position i, and bridge the stationary contacts 20 and 23, thus coi'inectingz,- the main 33 to the excit ing brush 9; thr ough the commuted winding- 5, the other exciting brush 8, and the part 41 of the stator winding. After the machine has reached a certain speed, the weights i5 canso the movable contacts 16 and ll to travel. upward and to occupy the position in this position the connection betw the tionary contacts 20 and S23 is maintninc and contacts 18 and 1%) are interconnected b means of the blade 1'1, thus connection th main 33'to one end of the total stator wind-- ing while the main. 32 remains connected to the other end said winding. The closing of this circuit also closes a local circuit iucluding the stator winding parts 10 and 11 and the commuted winding 5, by way of the brushes 9 and'8, A further upward'niotion of the blades 16, 1?, controlled by the weights 15, brings the centrifugal switch in its third position and interrupts the connection between the stationary contacts 20 and 23, thus opening the local circuit referred to. The final operation performed by the centrifugal switch, when it reaches its position 41-, consists, in bridging" the stationary contacts 21 and 23, thus forming a local circuit including the commuted winding 5 by way of the brushes 8, 9, and the part 10 of the stator winding.

The number of turns of the part ll of the stator winding is so chosen as to givethe the circuit being completed de ir d combination with the seconnnuteo winding. The number of n the compiete stator winding, in-

parts il, 1 3 and. i1, is chosen so as to 'most suitehie working densities in he, while the number of turns in the it of the stator winding selected so oproduce desired degree of comtion when that winding is connected to reciting bruslries after the motor has hed normal speed, In the position 1 he centrifugai switch, only part 41 of stator winding is in circuit. In the secposition of saidswitch, the whole of the r winding is in circuit, but the compen- E. M. F. impressed on the exciting es 8, 9, is derlyed from the parts 10 ii. of the stator winding. In the posi 3 of the centrifugal switch, the pre- 12 compensating circuit is interrupted z.ut nae machine is kept running, the squirra e producing the necessary motor 3 J rotation in the flux due to the stator i1, 10 and 11.' In the final or e. position of the centrifugal. switch, .lhole stator Winding is still in circuit, 1 compensating E. F. is exciting brushes 8, 9, being e part 10 of thestator windt 10 may be chosen to produce p use compensation. In this starting conditions are made :endent oi the running conditions 0 may be operated in both cases the most- ;t'orvorabie circumstances.

" Iuiiy described my invention, 'm as new and desire to secure by n oi" the United States is:

nbinati'on with source of alter- .nt, of a motor having a stator ....1 a a compensa .ing and an auxiliary winding, all coaxially disposed, a rotor having a permanently short-circuited winding, a commuted winding, short-circuited working brushes in the axis of the stator windings and exciting brushes displaced therefrom, the main stator winding and exciting brushes being connected in series and to the source at starting means for connecting the compensating and auxiliar stator windings to the source-in series with the main winding and in shunt to the exciting brushes, and means for disconnecting the source from one exciting brush and for connecting the compensating winding in 'shunt to the exciting brushes.

2 The combination with a source of alternating current, of a motor having a stator provided with a main, a compensating and an auxiliary winding, all coaxially disposed, a rotor having a permanently short-circuited winding, a commuted winding, shortcircuited Working brushes in the axis of the stator windings and exciting brushes displaced thercfrom, the main stator winding and the exciting brushes being connected in series and to the source at starting, means governed by the speed of the motor for connecting the compensating and auxiliar stator windings to the source in series wit 1 the main winding and in shunt to the exciting brushes, for disconnecting the source from one exciting brush, and for. connecting -the compensating winding in shunt to the exciting brushes.

In testimony wher'e'ofiI have hereunto set my hand and. affixed my seal in the presence of two subscribing witnesses.

VALERE ALFRED FYNN. [L. 5.]

\Vitnesses:

' W'. A. ALEXANDER, G. M. SHORE. 

